One of the more interesting aspects is the WTMMTW configuration, rather than TMWWMT, which would have more closely followed the VP150 precedent.
It's better if you think of it as a TMMT configuration just like the VP150, but with a woofer tacked on at each end
Seriously, after playing around with some calculations looking at the impact of comb filtering, if you buy into that, this configuration does seem like the best one. My very informal experiments suggested that comb filtering is most noticeable in the midrange, so you want those drivers closest together. The wavelength of the frequencies handled by the woofers is so long that even the widest separation doesn't seem to be a problem, leaving the tweeters in the middle.
